[PATCH 5.17 073/114] usb: xhci-mtk: fix fs isocs transfer error

Greg Kroah-Hartman
2022-05-16T20:32:46Z

From: Chunfeng Yun <chunfeng.yun@mediatek.com>

commit c237566b78ad8c72bc0431c5d6171db8d12e6f94 upstream.

Due to the scheduler allocates the optimal bandwidth for FS ISOC endpoints,
this may be not enough actually and causes data transfer error, so come up
with an estimate that is no less than the worst case bandwidth used for
any one mframe, but may be an over-estimate.

Fixes: 451d3912586a ("usb: xhci-mtk: update fs bus bandwidth by bw_budget_table")
Cc: stable@vger.kernel.org
Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/20220512064931.31670-1-chunfeng.yun@mediatek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/usb/host/xhci-mtk-sch.c | 16 +++++++---------
1 file changed, 7 insertions(+), 9 deletions(-)

--- a/drivers/usb/host/xhci-mtk-sch.c
+++ b/drivers/usb/host/xhci-mtk-sch.c
@@ -465,7 +465,7 @@ static int check_fs_bus_bw(struct mu3h_s
*/
for (j = 0; j < sch_ep->num_budget_microframes; j++) {
k = XHCI_MTK_BW_INDEX(base + j);
- tmp = tt->fs_bus_bw[k] + sch_ep->bw_budget_table[j];
+ tmp = tt->fs_bus_bw[k] + sch_ep->bw_cost_per_microframe;
if (tmp > FS_PAYLOAD_MAX)
return -ESCH_BW_OVERFLOW;
}
@@ -539,19 +539,17 @@ static int check_sch_tt(struct mu3h_sch_
static void update_sch_tt(struct mu3h_sch_ep_info *sch_ep, bool used)
{
struct mu3h_sch_tt *tt = sch_ep->sch_tt;
+ int bw_updated;
u32 base;
- int i, j, k;
+ int i, j;
+
+ bw_updated = sch_ep->bw_cost_per_microframe * (used ? 1 : -1);

for (i = 0; i < sch_ep->num_esit; i++) {
base = sch_ep->offset + i * sch_ep->esit;

- for (j = 0; j < sch_ep->num_budget_microframes; j++) {
- k = XHCI_MTK_BW_INDEX(base + j);
- if (used)
- tt->fs_bus_bw[k] += sch_ep->bw_budget_table[j];
- else
- tt->fs_bus_bw[k] -= sch_ep->bw_budget_table[j];
- }
+ for (j = 0; j < sch_ep->num_budget_microframes; j++)
+ tt->fs_bus_bw[XHCI_MTK_BW_INDEX(base + j)] += bw_updated;
}

if (used)